Film cassete spool with exposure indicator
US5548368A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1995 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Jul 27, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B17/305
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A film spool of the type which is rotatable inside a light-tight cassette shell as a film strip coiled about the spool is pulled out of the shell, has a film exposure status indicator movable from a first position to a second position where it provides a visible indication that the film is completely exposed. The status indicator includes an element movable within the hollow interior of the spool core between the first and second positions, a spring urging the element towards the second position, and a retaining device cooperating with an end portion of the film strip to prevent movement of the element until the film strip has been fully unwound.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.